Study of mode recognition in 10 kV cable networks for organizing protection against single-phase ground faults

Relevance. Distribution networks account for the largest share of Russia's power grid. The most common fault type in these networks is a single-phase ground fault. Selective identification of the faulty cable line can prevent its escalation into a three-phase fault, improving power supply reliability. Purpose. A multiparameter method of ground fault protection uses several electrical quantities to determine the network mode. This method makes the protection selective and more sensitive. Different electrical quantities are of different value for the mode recognition task. The goal of the research is to study the parameters of current and voltage that are used for relay protection. Investigation of the ability to recognize network mode based on this parameters. Methods. We obtained statistics by using simulation modeling of the cable network in the Matlab software package in the Simulink expansion package in all possible modes. And then we used discrete Fourier transform of the full period to obtain filtred harmonics and quadrature components of the values of zero-sequence currents and voltages. Results. The article describes the block and functional diagrams of measuring elements that uses the dependencies of electrical quantities are proposed. The article determines the areas formed by electrical quantities on the graph in different modes such as internal and external steady-state single-phase ground faults and arc intermittent single-phase ground faults. The graph consists of the dependence of two electrical quantities. It was also revealed that the areas of different modes have mutual intersections. Conclusions. The results of the study are suitable for the implementation of multiparameter protection.